I passed the scjp6 with 87%, and i have a friend who passed the exam too with 88%, we both studied with kathy sierra books, I think is the best book in order to get the certification. In addition, we neither read any other papper, book, overview, etc. The kathy sierra is a good book for several reasons, first, you can get a self test at end each chapter, beyond, if you buy the book, it come with a cd that have two master exams, the difficulty of the questions in both exams are similarity of the real exam. Finally, we take several mock exams, specifically, mock exams of whizlab. I think, with mock exams and kathy sierra book you will be able to take the exam. good lucky.